Double casing pump



Feb. 9, 1954 Ross 2,668,503

DOUBLE yCASING PUMP Filed OCT.. 26, 1949 Patented Feb. 9, 17954 `DOUBLE CASING PUMP Hugh L. Ross, Shorewood, Wis., assignor to Allis- Chalmers Manufacturing Company, Milwaukee,

OFFICE Wis., a corporation of Delaware Application October 26, 1949, Serial No. 123,768 1 Claim. (Cl. 10S-111) l This invention relates to multiple stage double casing pumps. More specifically this invention relates to that type of double casing pump especially designed for pumping liquids at relatively showing an embodiment of the invention and forming a part of this application, and all these novel features are intended to be pointed out in the claim.

high pressure and temperature. The principal 5 Referring to the drawing, the pump comprises object o1" this invention is the provision of a new an outer casing IU divided into an intake chamand improved liquid pumping machine. ber II and a discharge chamber I2 separated by The double case type Dump generally @Omprises an annular projection I3. An inlet passage I4 an inner pumping casing that is spaced within transmits liquid at intake pressure to the intake an outer pressure casing. The inner casing conchamber II. A discharge passage I5 transmits tains impellers and annular passages for guiding the liquid from the discharge chamber I2 at disthe liquid through the pumping stages. The charge pressure. The outer casing I0 is open outer casing is generally divided by an annular at the discharge chamber I2 end of the casing. projection into an intake chamber and a dis-- This open end is iitted with a casing cover AI6 charge chamber. The inner casing is fitted withl5 which is attached to the outer casing III by means in the outer casing and is seated against the anof bolts Il, and a liquid tight seal is insured by nular projection with the rst stage impeller or a gasket which is set in a recess 2I to avoid impellers taking suction from the intake chamthe possibility of blowing out. An inner casing ber and. discharging the liquid after passing 22 is inserted into the open end of the outer casthrough all of the stages into the discharge cham- 2o ing I I) and mounted therein. The casing 22 may ber of the outer casing. The intake end of the comprise two axially extending halves bolted toinner casing is held tight against the annular seat gether according to the conventional practice of bythe discharge pressure in the discharge chamthe prior art, as shown by the U. S. patent to ber. This leaves the end of the inner casing re- Hollander, No. 1,655,546, to afford the structure mote from the annular seat free to move axially which can be easily assembled and disassembled. relative to the outer casing as the inner casing The radial shoulder 23 of the inner casing 22 is expands and contracts in response to changes in seated against the annular projection I3 within temperature and/or pressure within. the outer casing II). The inner casing 22` is held The invention is especially useful whenV applied iirmly against the projection I3 by the discharge' to pumps supplying feed water to boilers at high 5o pressure of the liquid within the discharge chamtemperature and pressure. Under such circumber I2. A gasket 24 is tted between the shoul-V stances the axial movement of the inner casing der 23 and the projection I3 to provide a liquid relative to the outer casing may be quite subtight seal between the intake chamber II and the stantial and frequent as changes in demand are discharge chamber I2. Bolts 2'5 provide an initial made upon the pump. Accordingly, it is a priseal and keep the inner casing 22 in position durmary object of this invention to provide means ing periOdS 0f Startins' and Stopping When the to seal the inner and outer casings, as the re1apressure Within the discharge Chamber I2 may tive axial positions thereof are changed in re- 110i? be enough t0 maintain the Seal- Keys 25, 2`I sponse to changes in pressure and/or temperature alSO aid in Supporting the inner Casing 22 in within the inner casing. 4o proper alignment, in that they keep the inner It is also an object of this invention to provide Casing 22 from turning Within 12h@ 0111761' Casing l0. 3, pump 0f the aforementioned type in which A shaft 28 is disposed in the inner casing 22 means controlling the seal of both the inner and find extends ih lOuh both ends 0f the Outer casouter casings are external to the outer casing. lng lil- A SelleS 0f annular passages -29 to 35 Another object of invention is to provide dlrect the through the inner Casing 22. o pump of the aforementioned type in which Impellers 36 to 43 are mounted on the shaft in packing for sealing both the inner casing and the the annular passage 29 tOi-'l5- outer casing can be inspected, tightened or re- The pressue Of'tlile illd as il? DaSSeS through placed Without dismetntiing the outer casing the inner casing 22 1s raised in a series of stages Objects and advantages other than those above 5o herem numbeled through 7- The first Stage Set forth Wiii be 2Jpparent as the description of comprises two impellers 36, 31 both of which take the invention proceedsl suction from the intake chamber I I and discharge The novel features of the invention and how into the passages 29 which direct the fluid to the the objects are attained will appear from the ODDOSS end 0f the inner Casing 22, Where the specication and the accompanying drawing liquid enters stage 2- The liquid isthen directed through the remainder of the stages 2 to 1, which have a single impeller 38 to 43 in each, and the path of the liquid is indicated by the passages numbered 30 to 35. The fluid passes from the final pumping stage 1 to the passage 35 which discharges into the discharge chamber i2 of the outer casing l and the iiuid is then discharged from thelpump through the discharge passage I5. The arrangement and location o'f the stages further described and claimed in the copending application of Edward J. Blackwell, Serial No. 123,719, iiled October 26, 1949. As far 'as'the invention of the present application is concerned, other arrangements may be used.

The arrangement and number of stages as illustrated results in having between stage i and stage 5, fourth stage pressure in the fluid passage 32 adjacent the passage 29 having first stage pressure therein, and between stage 'I and stage 4, seventh stage pressure in `the passage 35 adjacent th'e passage 32 having fourth stage pressure therein. The high differential in pressure at these two locations requires suitable high pressure sealing means B l 82 to reduce leakage of the high pressure liquid into the passage of lower pressure, resulting in a lossfof pump efficiency. The construction of this high pressure sealing means 8i, 82 may be of the form as here shown and more fully 'described and claimed in the eopending applicationl of Milton W. Lutz, Serial No. 123,856,

filed October 29, 1949. As far as the invention of the present application is concerned other sealing means may be used.

Means to allow axial expansion of the inner casing Z2 relative tothe outer casing i9, in response `to changes in pressure land/or temperature within the inner casing 22 are herein disclosed as comprising a collar E, an annular member 5i, and sealing means. The sealing means are further disclosed as comprising glands 52,

a bleed off bushing 54, and packing 55, 56.

The collar 58 is spaced about the shaft 25 and is integral with the end wail of the inner casing 22. The-annular passage transmits the fluid from: the two stage I impellers 3s, v3'! to the stage 2 impeller 38 at thev opposite end of the pump` The intake forthe stage 2 impeller i'is within the area. of the end wall enclosed by the collar 59. The'member 5i is fitted to the collar es and attached thereto by bolts 5l that pass through a flange 58 extending radially from the member 5l. The member 5l extends through an opening et, of approximately the same diameter as the member'5l1, in thecasing cover I6. The opening Gs is countersunk to provide space for the packingv 55.' The gland 52 fits. about the outer diameter ofthe memberv 5l and bolts 6i provide the meansV for forcing the glands against the packing 55,1 therebyeiectin'g a liquid tight seal between the" inner surface off the opening Bs and the outerV surface ofthe member 5i extending therethrough. The inner diameter of the member 5l' larger than the` outer diameter ofthe shaft- 28 thereby' providing space for the packing fr sleeve 62' is-iitted tothe shaft 28 and the bleed oi bushing 5i is. mounted. about the sleeve 52' and Viittedtothe member 5I by an annular projection 53. A A bushing retaining ring 64 is' fitted to the' member 4 5I and the bushing 54. Bolts 65 hold the ring 64 rmly to the member 5l and the bushing 5l is thereby securely held in place. Packing 56 is inserted in the remainder of the space about the shaft 2B. Pressure is exerted upon the packing 56 by the gland 53 which is drawn up by bolts 66 tted through the gland 53 and engaging the member 5l.y Liquid that pa's'ss 4tliebushing 54 bled off through a passage 61 'and such liquid is reintroduced into the pump intake.

From the foregoing it will be apparent to those 'skilled in the art that the illustrated embodiment of the invention provides a new and improved liduid pumping machine and accordingly la'ccmmplishesv theobjects of the invention. On the other hand, it will also be obvious to those skilled in the art that the illustrated embodiment of the invention may be variously changed and modified, or features thereof, singly or collectively, embodied in other combinations than those illustrated, without departing from the spirit of the invention, or sacrificing all' ofthe advantages thereof, and that accordingly the dis: closure herein is illustrative only, and the inverition is not limited thereto.

It is claimed and desired to secure by Letters Patent:

Av double casing for a multistage .centrifugal pump comprising: an integral outer pressure cas-- ing having an open end, an inner-pump casing mounted in spaced relation within said outer cas` ing, a shaft journaled in said inner casing ex tending axially therefromvto the exterior of said pump, an integral annularcover dening a single uninterrupted cylindrical internal surface radially spaced about said shaft, said cover beingdetach. ably secured to said open end of said outer casing to close said open end of said outer casing, said inner casing having end wall means terminating in an annular portion radially spaced from said shaft, a one piece annular member radially spaced about said shaft and attached to said .innercasing end wall means, said annular member ex;` tending through said cover and being :movable relative thereto in response to axial expansion of said inner casing, saidmember presenting a single uninterrupted cylindrical externalsurface com` plementary to said internal surface of said cover and cooperating therewith to withstand the full discharge pressure of said pump to atmosphere, iirst sealing ymeans positionable externally of said cover cooperating with said surfaces to seal said` annular member to said cover in all relative' axial positions thereof, and second sealing means posi-`V tionable externally of said cover for sealing said member against ksaid shaft.

HUGH L. ROSS.

References' Cited the le' of this patent UNITED STATESI PATENTS 

